Pharyngeal size in snorers, nonsnorers, and patients with obstructive sleep apnea

We measured pharyngeal cross-sectional area and its change with alterations in lung volume in 10 subjects who snored and had obstructive sleep apnea, 6 subjects who snored and did not have obstructive sleep apnea, and 9 subjects who did not snore. Pharyngeal area was measured with use of an acoustic-reflection technique. We found that snorers with and without sleep apnea had a significantly smaller mean (+/- SE) pharyngeal cross-sectional area (4.1 +/- 0.2 and 3.7 +/- 0.9 cm2, respectively) at functional residual capacity than nonsnorers (5.4 +/- 0.5 cm2, P less than 0.025). When lung volume decreased from functional residual capacity to residual volume, both nonsnorers and snorers with sleep apnea had a decrease in pharyngeal area (from 5.4 +/- 0.5 to 4.5 +/- 0.4 cm2 and 4.1 +/- 0.2 to 3.4 +/- 0.2 cm2, respectively), whereas snorers without sleep apnea had no such decrease, suggesting that their pharynxes were less collapsible at low lung volumes. We conclude that snorers with and without sleep apnea have smaller pharyngeal cross-sectional areas than nonsnorers and that snorers with sleep apnea have a further decrease as lung volume falls.     

The infrapyloric artery and cephalic pancreatoduodenectomy with pylorus preservation: preliminary study

Summary Cephalic pancreatoduodenectomy (CPD) with pylorus preservation has been suggested to improve the functional and nutritional result of surgery. At operation, the first two centimeters of the duodenum are preserved, the vascular arch of the lesser gastric curvature is saved and the right gastroepiploic artery is resected at its origin. The aim of this study on 15 fresh cadavers was to determine the origin of the vascularization of the remaining duodenum and also the possibilities of preserving an optimal vascularization after CPD and pylorus preservation. All of the arteries supplying the remaining duodenum and arising either from the right gastric artery or the right gastroepiploic artery were identified. The distances between the origin of the infrapyloric artery and the termination of the gastroduodenal artery on the cranial and ventral pancreaticoduodenal artery and the left gastroepiploic artery were measured. At CPD with pylorus preservation, the study demonstrated that: 1) the cranial side of the remaining duodenum remains vascularized in 80% of the cases by one or two supraduodenal branches coming from the right gastric artery; 2) ligation of the right gastroepiploic artery eliminates all vascular supply to the caudal side of the remaining duodenum in almost half of the cases; 3) in these cases, the dissection of the bifurcation of the gastroduodenal artery and the vascular section beyond the origin of the infrapyloric artery allowed a direct vascular supply to the remaining duodenum to be preserved.This work was presented at the French Section of the European Association of Clinical Anatomy meeting, Bobigny, France, 1992     

Studies on the cytosolic estrogen receptor from rat thymus

The estrogen receptor present in rat thymus cytosol was characterized by its association constant, KA, the number of binding sites present, Bmax, and by the effect of added estradiol on the binding parameters. The binding parameters were determined by fitting the raw binding data directly to the hyperbolic binding function, and the Lineweaver-Burk, Scatchard, and Woolf linear transforms of the hyperbolic function. The binding parameters were also determined using the direct linear plot method of Eisenthal and Cornish-Bowden. The Woolf plot and the direct linear plot gave results that indicated that added estradiol caused both competitive and noncompetitive inhibition of the receptor. The Scatchard and Lineweaver-Burk methods were not capable of showing a systematic trend. The parameters derived from the hyperbolic binding equation were in agreement with the Woolf and direct linear plot methods. The results of this study show that the cytosolic estrogen receptor from rat thymus is both competitively and noncompetitive inhibited by estradiol.     

Volume and surface area estimates of astrocytes in the sensorimotor cortex of the cat

Electron micrographs of random sections through 133 astrocytes taken from the anterior and posterior sigmoid gyri of adult cats were used to estimate average astrocyte cell volume. Average soma volume was derived by two methods: (1) assuming that each approximated the shape of a prolate spheroid, a value of 2.2 ± 0.1 × 10^?13l. was calculated by substituting measurements of major (mean 10.4 ± 0.2 μm) and minor (mean 6.2 ± 0.1 μm) cell axes into the formula for volume; (2) applying Weibel's point-counting method of morphometry, a value of 1.9 ± 0.09 × 10^?13l. was obtained based on ratios of volume density and nuclear volume, calculated from measurements of nuclear axes. Because of the use of random sections through the cells sampled, the axial measurements on which both methods depend represent possible underestimations by as much as 21%; the resulting average value for soma volume might be as much as 3.2 × 10^?13l. Astrocyte somata from the deepest layer of the cortex had a significantly larger average volume than those from more superficial layers (P < 0.05). Average total cell volume (soma plus processes), estimated by calculating the volume of the tissue sample that was occupied by astrocytes and dividing that value by the number of astrocytes in the sample, amounted to 5.7 × 10^?13l. Point-counting morphometry revealed that 15.5% of the cortex consists of astrocytic cytoplasm. Average total cell surface area, estimated from intercepts of grid lines with cell membrane profiles of astrocytes within the sample, was 1.9 × 10^?5 cm²; average surface area of astrocyte somata, based on axial measurements, amounted to 2.5 × 10^?6 cm² or 13% of the surface area of the whole cell.Only 18 gap junctions were identified in the random sections through 133 astrocytes; these and other considerations bearing on the possible relationship of the data presented to electrical measurements in living astrocytes are discussed.     

Effect of atropine and vagotomy on response of transplanted pancreas.

It is well established that atropine and vagotomy inhibit pancreatic enzyme secretion in response to intestinal stimulants such as fat or amino acids. These effects are usually attributed to interference with hypothetical vagal cholinergic mechanisms that facilitate release of cholecystokinin. To determine whether atropine or vagotomy interferes with release of humoral stimulants of pancreatic enzyme secretion, we studied their effect on protein secretion from an autotransplanted portion of pancreas in response to intestinal stimulants in dogs. The transplanted pancreas was as sensitive as the intact pancreas to stimulation by exogenous caerulein, a cholecystokinin-like peptide, and this response was not altered by atropine or vagotomy. Therefore, if vagotomy or atropine interferes with release of humoral pancreatic stimulants, they would be expected to reduce the response of the transplanted pancreas just as they do of the intact pancreas. Truncal vagotomy caused no significant change in protein secretion from the transplant in response to intestinal perfusion with sodium oleate or tryptophan. Atropine was tested only against sodium oleate and caused no change in response. We conclude that release of humoral pancreatic excitants of protein secretion in response to intestinal stimulants is not significantly changed by atropine or vagotomy.